Designing of Straw Chopper Machine for Compost Production

Abstract

Amount of straw wastes in Ciparay, Bandung, West Java Indonesia reaches 10-12 tons.ha-1 but its has not been well managed, after harvested, the remaining unused straw is abandoned on the ground and is eventually burned. In the long run, this straw burning will be very disadvantageous to farmers, especially in terms of the environmental impacts on rice paddy including decreasing soil fertility, killing soil biota, damaging soil physical properties and wasting energy. One of alternatives to utilize rice straw able to provide added value is utilizing its waste as a material to make compost on the condition that the straw is already chopped into a size of 5-10 cm according to SNI standards. Therefore, a study on rice straw chopping technology based on the composting requirements is required. The aim of this study is to design a prototype of rice straw chopper with capacity 100 kg.hr-1. The method used in this research is engineering design with observation of the reasearch, design criteria, functional and structural design, figure design, technical analysis, prototyping of rice straw chopper, machine functional and performance test. The measurement results of rice straw characteristics show that the average length, diameter, bulk density and moisture content of rice straw are 708 mm, 4 mm, 160.6 kg.m-3 and 34.6% wet basis. This straw chopper design were produces a prototype with a dimension of 1040 mm (length) x 1000 mm (height) x 465 mm (width) with a power source generator using 5.5 HP gasoline motor. The result of functional test of the straw chopper shows that the actual capacity of this straw chopper is 100.32 kg.hr-1.